Aim
To synthesise fluoridated hydroxyapatite (FA) crystals directly on preformed metal crowns (PMCs) and evaluate the anti-cariogenic properties in an in vitro model.
Conclusion
FA-coated PMCs demonstrated carious lesion preventing effects, i.e. fluoride release and reduction of demineralisation at crown/tooth interface. FA-coated crowns could be an aesthetic, inexpensive and caries preventive alternative in clinical dentistry.
Methods
FA crystals were grown on etched PMCs and stainless steel discs and characterised by SEM. FA-coated discs allowed fluoride release to be assessed from a known surface area of FA crystals. Discs were divided into four groups (n = 6/group) and exposed to solutions at pH 4-7. Fluoride levels in solution were measured after each exposure. Twelve FA-coated and 12 non-coated PMCs were cemented onto human molars using glass ionomer (GI) or unfilled resin, making four groups of six teeth; FA-coated + GI, FA-coated + resin; non-coated + GI and non-coated + resin. Teeth were exposed to acidified gelatin (pH = 4.3) for 9 weeks.
Results
SEM showed FA crystal growth on interior and exterior of the crowns. Average fluoride release from FA-coated discs was 0.16 mg/L/cm² at pH < 5.0. Teeth were sectioned through the lesion. Polarised microscopic examination revealed significantly smaller lesions in FA-coated crown groups compared to non-coated crown groups.